A method for improving the quality of water guide laser drilling

Abstract

The application provides a method for improving water guide laser drilling quality, which uses a two-step method of drilling and hole repairing to carry out water guide laser drilling, first, through single factor experiment, influences of various processing parameters on hole roundness, hole taper, processing efficiency and microscopic defects are analyzed, and the best parameter combination for processing vertical hole is determined, in the drilling stage, the drilling quality is optimized by using laser power, scanning feed number, scanning path overlap rate and scanning time in the best parameter combination; and in the hole repairing stage after the hole is penetrated, the hole wall is finely processed by controlling laser power and scanning speed, so that the quality and efficiency of cobalt-based superalloy drilling are improved. Moreover, for the discontinuity problem of single path processing, the application forms a closed path by optimizing the scanning path, so that the continuity of micro-hole processing can be realized, thereby the processing time is shortened and the processing efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of metal processing technology, and specifically to a method for improving the quality of water-guided laser hole drilling. Background Technology

[0002] Water-guided laser technology combines high-energy lasers with high-speed water flow. Through the guiding effect of the water flow, it can effectively improve the precision of laser processing and has excellent micro-hole processing capabilities. However, significant technical bottlenecks still exist in the actual processing.

[0003] When cobalt-based superalloys are processed by water-guided laser drilling, the traditional one-step drilling method cannot produce high-quality microholes. There are large defects on the hole wall, and there is also considerable room for improvement in hole taper and roundness. Furthermore, the processing is discontinuous due to the path.

[0004] Currently, there are two main scanning paths: spiral drilling and concentric circle drilling. In spiral drilling, the laser beam starts from the innermost point of the spiral path and moves outwards along the spiral trajectory at a constant speed V until it reaches the outermost end. This processing cycle is defined as one layer. Although this path can reduce the width of the HAZ (heat-affected zone) to some extent, due to the discontinuity between layers, multi-layer processing is usually required. Furthermore, after processing the same layer, an "unclosed defect" may form around the hole due to the non-closed path. While this defect can be compensated for by setting a compensation path around the hole, it increases the HAZ width and the complexity of programming.

[0005] Although concentric circle paths do not suffer from the aforementioned "non-closed defect" problem, the HAZ width still increases when the laser beam scans multiple times within the same circle. The lack of continuity between different concentric circles is essentially similar to spiral drilling, still belonging to layered processing, which affects hole taper, hole roundness, and processing time.

[0006] During the two-step hole-making process, the processing parameters were not adjusted during the hole-finishing stage, resulting in the accumulation of high energy on the hole wall and the formation of a thick HAZ, which in turn resulted in a thick recast layer on the hole wall after processing.

[0007] Therefore, an optimized water-guided laser drilling method is needed. Summary of the Invention

[0008] This invention addresses the quality defects and discontinuous processing issues inherent in traditional water-guided laser hole drilling. It proposes a method to improve the quality of water-guided laser hole drilling. First, by optimizing the drilling path, a closed path is achieved, ensuring continuous micro-hole processing. Second, the drilling process is divided into two parts: drilling and finishing. In the drilling stage, processing efficiency and HAZ width are optimized by controlling laser power, scanning feed number of revolutions, scanning path overlap rate, and scanning time. In the finishing stage after hole penetration, fine machining of the hole wall is performed by controlling laser power and scanning speed, thereby improving the quality and efficiency of drilling cobalt-based superalloys.

[0009] This invention provides a method for improving the quality of water-conducting laser-guided hole fabrication, comprising the following steps: S1. After cleaning and drying the material to be drilled, fix it on the machine tool; S2. Set the drilling parameters for the water-guided laser processing head; S3. The water-guided laser processing head continuously drills holes in the material to be pierced using a composite processing path until it penetrates through the material. The composite machining path is a closed path consisting of n clockwise concentric circular paths and n-1 clockwise upward spiral paths and n-1 clockwise downward spiral paths located between two adjacent concentric circular paths. The concentric circle paths are set sequentially from the inside out as the first concentric circle path, ..., the second concentric circle path. i The path consists of concentric circle paths, ..., the (n-2)th concentric circle path, the (n-1)th concentric circle path and the nth concentric circle path, where 1 ≤ i ≤ n-2, and the leftmost endpoint of the first concentric circle path is the startpoint. The spiral paths are arranged sequentially from the inside out as the first spiral path, ..., the second spiral path. i The spiral path consists of the (n-2)th spiral path and the (n-1)th spiral path. i The upward spiral path is externally tangent to the first... i The leftmost endpoint of the concentric circles transitions to the point inscribed in the first concentric circle. i +1 The rightmost endpoint of the concentric circles; The downward spiral paths are arranged sequentially from the inside out as the first downward spiral path, ..., the third downward spiral path. i The spiral path consists of the n-th spiral path, ..., the (n-2)th spiral path and the (n-1)th spiral path. i The downward spiral path is inscribed in the first... i +1 The rightmost endpoint of the concentric circles transitions to the externally tangent point at the first... i The leftmost endpoint of the concentric circles; During drilling, the coupled energy beam of the water-guided laser processing head starts from the startpoint and scans clockwise around the first concentric circle path, then enters the second concentric circle path along the first upper spiral path. After scanning around the second concentric circle path for one and a half cycles, it enters the third concentric circle path along the second upper spiral path, and so on, until it scans the nth concentric circle path. After scanning clockwise around the nth concentric circle path for one cycle, it enters the (n-1)th concentric circle path along the (n-1)th lower spiral path. After scanning around the (n-1)th concentric circle path for one and a half cycles, it enters the (n-3)th concentric circle path along the (n-2)th lower spiral path, and so on, until it scans the first concentric circle path, thus ending one cycle of composite processing path scanning. The composite processing path scanning is repeated until the material to be drilled is penetrated to obtain a through hole; S4. Use a circumferential cutting path to repair the outermost edge of the through hole; S5. After the hole is repaired, remove the material to be drilled, clean and dry it.

[0010] In a preferred embodiment of the method for improving the quality of water-guided laser hole drilling according to the present invention, in step S1, the material to be drilled is ultrasonically cleaned in anhydrous ethanol for 5 min to 10 min and then placed in a drying oven for 5 min to 10 min; the material to be drilled is then fixed on the motion platform of the machine tool by a pressure plate.

[0011] The method for improving the quality of water-guided laser drilling according to the present invention, as a preferred embodiment, includes drilling parameters including water pressure parameters, laser drilling power, path overlap rate, and number of drilling path scans n in step S2. The laser finishing parameters in step S4 are different from the drilling parameters.

[0012] In a preferred embodiment of the method for improving the quality of laser-guided hole forming in water-conducting systems according to the present invention, the laser hole-refining parameters in step S4 include laser hole-refining power and scanning speed. The power of laser hole trimming is less than that of laser hole drilling. The taper, roundness, and processing time of the hole are optimized by adjusting the laser finishing and drilling parameters.

[0013] The method for improving the quality of laser-guided hole drilling according to the present invention, as a preferred embodiment, involves a laser drilling power of 20W~50W and a laser repair power of 5W~20W.

[0014] In a preferred embodiment of the method for improving the quality of water-guided laser drilling according to the present invention, in step S2, the drilling parameters are obtained through single-factor experiments, and the effects of hole roundness, hole taper, processing efficiency and micro-defects are analyzed.

[0015] The method for improving the quality of laser-guided hole drilling according to the present invention, as a preferred embodiment, is that the material to be drilled is a cobalt-based high-temperature alloy, and the diameter of the micropore is 0.4~1.0mm.

[0016] The method for improving the quality of laser-guided hole fabrication according to the present invention, as a preferred embodiment, involves a conical hole as the through hole; step S5 yields a micro-hole; It also includes step S6: S6. After measuring and statistically analyzing the outlet and inlet diameters of the micro-holes under an optical microscope, the taper of the hole is calculated. The roundness of the hole is calculated using the least squares method. The hole wall and surface are then microscopically inspected using an electron microscope.

[0017] The present invention has the following advantages: This invention employs a two-step method for water-guided laser hole drilling: drilling and finishing. First, single-factor experiments analyze the effects of various processing parameters on hole roundness, taper, processing efficiency, and microscopic defects to determine the optimal parameter combination for processing vertical holes. During the drilling stage, the drilling quality is optimized by using the laser power, number of scan feed cycles, scan path overlap rate, and scan time from the optimal parameter combination. In the finishing stage after hole penetration, the hole wall is finely processed by controlling the laser power and scan speed, thereby improving the quality and efficiency of drilling cobalt-based superalloys. Furthermore, addressing the discontinuity inherent in single-path processing, this invention optimizes the scan path to form a closed path, achieving continuity in micro-hole processing, thus shortening processing time and improving processing efficiency. Attached Figure Description

[0018] Figure 1 A flowchart of a method for improving the quality of water-guided laser hole fabrication; Figure 2 A schematic diagram of a composite processing path for a method to improve the quality of water-guided laser hole drilling; Figure 3 Example 1: Schematic diagram of a micro-hole for a method to improve the quality of water-guided laser-fabricated holes. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example 1

[0020] like Figures 1-3As shown, a method for improving the quality of water-guided laser drilling, taking the water-guided laser processing of GH5188 (cobalt-based high-temperature alloy) as an example, divides the drilling parameter adjustment method into a two-step drilling and finishing process. The drilling parameters are used to control the distribution of laser energy on the hole wall, ensuring drilling quality and processing efficiency. The laser scanning path is set as a composite scanning path of spiral and concentric circles, improving drilling quality while maintaining processing efficiency. In the two-step drilling process, the laser power, number of scanning feed cycles, scanning path overlap rate, and scanning time are controlled during the drilling stage, while the laser power and scanning speed are controlled during the finishing stage. This optimizes the hole taper, hole roundness, and processing time, further improving drilling quality and efficiency.

[0021] This invention achieves continuity in micro-hole processing by optimizing the drilling path, thereby improving processing efficiency. Furthermore, by adjusting processing parameters during the finishing stage, it optimizes hole taper, roundness, and processing time. The two-step hole-making method, using a composite path for rapid through-hole drilling in the drilling stage and adjusting processing parameters in the finishing stage, effectively improves hole quality and reduces hole wall roughness. Compared to existing technologies, this invention not only maintains high processing efficiency but also significantly improves hole quality.

[0022] This embodiment includes the following steps: S1. Before processing GH5188 (thickness 4mm), place the material to be processed in anhydrous ethanol and ultrasonically clean it for 5min~10min, and then place it in a drying oven for 5min~10min. The GH5188 is fixed to the moving platform of the machine tool using a clamp (the clamp is a pressure plate); S2. Use a water-guided laser processing head with a diameter of 25~80μm (including a 3Nd:YAG laser that generates a wavelength of 532 nm), set the water pressure parameters to 200bar~300bar and the relevant parameters for processing GH5188, the laser power (P1) to 20W~50W, the path overlap rate (L) to 20%~80%, the number of path turns k of the composite processing path to be 5~10 turns, and the water jet flows out from the nozzle on the water jet device; the temperature of the water jet is 20℃~25℃. S3, according to... Figure 2 The composite path shown is used for drilling GH5188; the composite path is formed by the combination of concentric circles and spiral lines. This invention combines two paths to form a composite drilling path. The coupled energy beam scans clockwise from the innermost startpoint, completing one revolution before entering the blue number 2 concentric circle along the red spiral. After one and a half revolutions in number 2, the coupled energy beam continues along the red spiral into the number 3 concentric circle, and so on, until the outermost numbern circle. After completing one revolution of numbern, the coupled energy beam enters the numbern-1 concentric circle from the outside in along the yellow spiral, finally ending the scan at the innermost circle (number 1). This process is repeated until a micropore is formed. By combining the concentric circles and the spiral path to form a closed path, continuity between different revolutions can be achieved, thereby avoiding layered processing and improving processing efficiency.

[0023] S5. After the hole is detected to be through, the outermost hole edge is cut around in a circular path and the hole is repaired for 1 to 5 minutes. During the repair, the laser power (P2) is 5W to 20W and the scanning speed is 3 to 8mm / s. S6. After the holes to be repaired are finished, remove GH5188 from the fixture, then place it in anhydrous ethanol for ultrasonic cleaning for 5-10 minutes, and finally place it in a drying oven to dry. The micropores are as follows: Figure 3 As shown.

[0024] S7. Place the processed micropores under an optical microscope, measure and statistically analyze the inlet and outlet diameters of the micropores after processing, and calculate the taper of the pores. Calculate the roundness of the pores using the least squares method. Then, use a electron microscope (SEM) to perform microscopic inspection of the pore walls and surfaces.

[0025] In this embodiment, the micropore diameter is 0.8 mm, the minimum pore roundness is 2.03, and the pore taper is 1.023.

[0026] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for improving the quality of water-conducting laser-guided hole fabrication, characterized in that: Includes the following steps: S1. After cleaning and drying the material to be drilled, fix it on the machine tool; S2. Set the drilling parameters for the water-guided laser processing head; S3. The water-guided laser processing head continuously drills holes in the material to be drilled through using a composite processing path until it penetrates through the material. The composite processing path is a closed path consisting of n clockwise concentric circular paths and n-1 clockwise upward spiral paths and n-1 clockwise downward spiral paths located between two adjacent concentric circular paths. The concentric circle paths are arranged sequentially from the inside out as the first concentric circle path, ..., the second concentric circle path. i The path consists of concentric circle paths, ..., the (n-2)th concentric circle path, the (n-1)th concentric circle path and the nth concentric circle path, where 1 ≤ i ≤ n-2, and the leftmost endpoint of the first concentric circle path is the startpoint. The upper spiral path consists of the first upper spiral path, ..., the second upper spiral path, arranged sequentially from the inside out. i The spiral path consists of the (n-2)th spiral path and the (n-1)th spiral path. i The upward spiral path is externally tangent to the first... i The leftmost endpoint of the concentric circles transitions to the point inscribed in the first concentric circle. i +1 The rightmost endpoint of the concentric circles; The downward spiral path consists of the first downward spiral path, ..., the second downward spiral path, arranged sequentially from the inside out. i The spiral path consists of the n-th spiral path, ..., the (n-2)th spiral path and the (n-1)th spiral path. i The downward spiral path is inscribed within the first... i +1 The rightmost endpoint of the concentric circles transitions to the externally tangent point at the first... i The leftmost endpoint of the concentric circles; During drilling, the coupled energy beam of the water-guided laser processing head starts from the startpoint and scans clockwise around the first concentric circle path, then enters the second concentric circle path along the first upper spiral path. After scanning around the second concentric circle path for one and a half cycles, it enters the third concentric circle path along the second upper spiral path, and so on, until it scans to the nth concentric circle path. After scanning clockwise around the nth concentric circle path for one cycle, it enters the (n-1)th concentric circle path along the (n-1)th lower spiral path. After scanning around the (n-1)th concentric circle path for one and a half cycles, it enters the (n-3)th concentric circle path along the (n-2)th lower spiral path, and so on, until it scans to the first concentric circle path, thus ending one cycle of composite processing path scanning. The composite processing path scanning is repeated until the material to be drilled is penetrated to obtain a through hole; S4. Use a circumferential cutting path to repair the outermost edge of the through hole; S5. After the hole is repaired, the material to be drilled is taken out, cleaned and dried.

2. The method for improving the quality of water-guided laser-guided hole fabrication according to claim 1, characterized in that: In step S1, the material to be drilled is ultrasonically cleaned in anhydrous ethanol for 5 min to 10 min and then placed in a drying oven for 5 min to 10 min; the material to be drilled is then fixed on the motion platform of the machine tool using a pressure plate.

3. The method for improving the quality of water-guided laser-guided hole fabrication according to claim 1, characterized in that: In step S2, the drilling parameters include water pressure parameters, laser drilling power, path overlap rate, and the number of scanning circles n of the drilling path; The laser hole-refining parameters in step S4 are different from the drilling parameters.

4. The method for improving the quality of water-guided laser-guided hole fabrication according to claim 3, characterized in that: In step S4, the laser repair parameters include laser repair power and scanning speed; The laser repair power is less than the laser drilling power; The hole taper, hole roundness, and processing time are optimized by adjusting the laser hole finishing parameters and the hole drilling parameters.

5. The method for improving the quality of water-conducting laser-guided hole fabrication according to claim 4, characterized in that: The laser drilling power is 20W~50W, and the laser repair power is 5W~20W.

6. The method for improving the quality of water-conducting laser-guided hole fabrication according to claim 1, characterized in that: In step S2, the drilling parameters are obtained through single-factor experiments, and the effects of hole roundness, hole taper, processing efficiency, and micro-defects are analyzed.

7. The method for improving the quality of water-guided laser-guided hole fabrication according to claim 1, characterized in that: The material to be poreped is a cobalt-based high-temperature alloy, and the diameter of the micropore is 0.4~1.0 mm.

8. The method for improving the quality of water-guided laser-guided hole fabrication according to claim 1, characterized in that: The through hole is a conical hole; step S5 yields micropores; It also includes step S6: S6. After measuring and statistically analyzing the outlet and inlet diameters of the micropores under an optical microscope, the taper of the micropores is calculated. The roundness of the micropores is calculated using the least squares method. The microscopic inspection of the hole walls and surfaces is performed using an electron microscope.

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